THE ROLE OF IMIDAZOLINE RECEPTORS IN BLOOD-PRESSURE REGULATION

Using the ligands [H-3] clonidine and [H-3] idazoxan, nonadrenergic imidazoline preferring binding sites have been identified in a range of tissues from several species including man. These sites may represent a new family of receptors. An endogenous ligand and potential clonidine displacing substance has been identified. There is strong evidence for an involvement of the nonadrenergic imidazoline [H-3] clonidine labelled sites in the nucleus reticularis lateralis in blood pressure regulation, and some evidence for a role in sodium regulation in the kidney for the [H-3] idazoxan labelled sites. Some drugs which were previously thought to act via alpha2-adrenoceptors, may mediate their effects in part via these imidazoline sites.